This invention relates to improvements in a fixture for firmly supporting a golf club or iron in a predetermined alignment with respect to the fixture to facilitate checking and adjustment of the loft and lie angles of the club in accordance with the requirements of a specific golfer.
The geometry and nomenclature of the parts of golf clubs are well known to the art, but are briefly reviewed for the sake of reference herein. A typical set of irons includes nine clubs numbered #1 through #9, a pitching wedge, and a sand wedge. Each club comprises a shaft interfitted at its lower end coaxially with a hosel that merges downwardly with a neck, which in turn merges outwardly with the club head. The latter has a heel that merges upwardly with the neck and outwardly in a rounded edge with a bottom sole which merges at an outwardly and upwardly rounded edge with a toe. The head also has a plane forward face bounded by the neck, heel, sole, toe, and a top edge that extends from the toe to the neck. The face has a plurality of parallel score lines thereon and, when the score lines are horizontal and the axis of the hosel is contained in a vertical plane parallel to the score lines, that axis intersects the horizontal at a lie angle and the plane of the face intersects said vertical plane at a loft angle, and typically, any plane normal to the score lines intersects the sole along a horizontal line.
Although the loft and lie angles may vary slightly between clubs of different brand names, a standard referred to herein is unofficially recognized by some of the major golf club manufacturers wherein the loft angle increases 4.degree. between successively numbered clubs, starting at 17.degree. for the #1 iron, except that the loft angle differs by only 3.degree. between the #2 and #3 irons and between the #3 and #4 irons, and wherein the lie angle increases 1.degree. between successively numbered irons, starting at 56.degree. for the #1 iron, except the lie angle for the #8 and #9 irons is 63.degree. and the lie angle for the pitching and sand wedges is 64.degree..
Various fixtures known heretofore for use in adjusting the loft and lie angles clamp the face and rear surface of the club head at a predetermined position between clamping jaws or shoes whereby the loft and lie angles are compared to a reference angle and the hosel is then bent with a suitable tool similar to a pipe or rod bending tool to effect the desired adjustment. Usually the club head is clamped with its plane face in a vertical reference plane, (or sometimes a horizontal reference plane) from which the angle of the club shaft is measured and adjusted, but without reference to any standard loft and lie angle.
The club is then removed from the fixture, tested in use to determine if the adjustment was adequate. If the adjustment was not adequate, the procedure is repeated until the club is satisfactory. A difficulty encountered with such fixtures is the almost impossibility of clamping the club a second time at the same position as the first, so that the second adjustment, if required, may render the club less satisfactory than before. Also the hosel cannot withstand many adjustemtns without being damaged or being bent irreparably out of shape. Also with the face of the club clamped in a horizontal or vertical plane, it is difficult or impossible to visualize the club in its normal operating position during the adjustment.
The wide variety of shapes for the different club heads in a set of irons, as well as the different shapes of comparable irons provided by different manufacturers, causes difficulty in clamping all club heads by means of any single fixture available heretofore, and especially between ordinary parallel clamping jaws. Thus, in order to clamp heads of various shapes between the same pair of clamping jaws, and to hold the head firmly against movement during a bending adjustment of the hosel, such extreme clamping force is required that permanent indentations are often forced into the head by the clamp. Such damage to the head can be avoided by removing the club from the fixture after measurement of the loft and lie angles, then adjusting these angles by bending the hosel and then replacing the head in the fixture to determine the extent of the adjustment. However such a procedure is obviously laborious and unsatisfactory and as aforesaid the difficulty of repeatedly clamping the head at the same angle or relationship with respect to the measuring device makes an accurate adjustment impossible.
An object of the present invention is to provide an improved golf club clamping fixture which enables the head of an iron to be readily clamped firmly, positively and repeatedly in the same angular relationship with respect to the fixture and a protractor device thereon for determining the loft and lie angles, with the club in an operative position whereat the plane of the face is at the standard loft angle and the axis of the shaft is at the lie angle.
Another object is to provide such a fixture that is readily adjustable to various standard loft angles and which is cooperable with improved protractor means engageable with the shaft clamped in the fixture for directly determining the lie angle and the deviation of the club face from the standard loft angle.
Other objects are to provide such a fixture having a plane indexing surface that is precisely adjustable to each of the standard loft angles and associated with improved aligning and clamping means for clamping the head of an iron (with its face flush with the indexing surface and with the score lines horizontal) sufficiently rigidly to enable bending adjustment of the hosel, and to provide such a fixture wherein the clamping means includes a fixed shoe for supporting the club head in predetermined and readily repeatable alignment with respect to the indexing surface and protractor means, wherein the clamping means also includes an improved second shoe movable in a clamping action parallel to the indexing surface and having a rounded cam arranged to engage the top edge of the head tangentially in a cam action for camming the head into clamping engagement with both the fixed shoe and the indexing surface.
Still another important object is to provide such a fixture wherein the fixed shoe engages the sole of the head at an acute angle with respect to the indexing surface to cam the head against the latter surface during the clamping action, and wherein the mounting for the second shoe enables limited lost motion for the latter shoe during the clamping action, such that as its rounded cam engages the inclined top edge of the head at any of the typical angles associated with the various types and makes of clubs, the cam portion readily adjusts itself with respect to both the thickness and the angle of the top edge to effect the desired camming and clamping action.
Other and more specific objects are to provide such a fixture wherein the fixed shoe is shaped to engage the head at and only at the two locations of the rounded upturned ends of the sole that merge with the toe and heel respectively, such that when the score lines are horizontal, the head will be in a predetermined position that can be readily and accurately relocated as often as desired; wherein the rounded cam engages the top edge at a predetermined location adjacent its mid-region between the toe and neck in cooperation with the lower fixed shoe to effect a three point clamping engagement that positively secures the head in a predetermined fixed position and enables the bending adjustment with a minimum of clamping force, thereby to avoid deformation of the head; wherein the indexing surface is adjusted to various standard loft angles by swinging about a horizontal pivot axis parallel to and adjacent a vertical plane that contains the lower most portion of the face and is parallel to the score lines when the club head is clamped in the aforesaid predetermined alignment; wherein the plane of the indexing surface at its various positions of angular adjustment is adjacent and parallel to its horizontal pivot axis; wherein the protractor means comprises an assembly mounted to swing about a vertical axis near the last named vertical plane toward and from the latter plane and also to move radially toward and from the vertical axis, the protractor assembly including a loft angle indicator having a shaft engaging surface and adapted to swing about said vertical axis to a position adjacent and parallel to said vertical plane into engagement with a portion of the club shaft adjacent the hosel when the club head is clamped in said predetermined alignment, the loft angle indicator being also pivotal from the vertical plane about a horizontal pivot axis to a position flush with the shaft portion to indicate the latter's deviation from the standard loft angle; and wherein the protractor assembly also includes a straight edge lie angle indicator pivotally mounted on the loft angle indicator for swinging into engagement with a second portion of the club shaft adjacent the hosel about an axis normal to both the horizontal pivot axis of the loft angle indicator and the axis of the hosel when the plane surface of the loft angle indicator is parallel to the latter axis, thereby to enable alignment of the lie indicator edge with the second shaft portion to determine its lie angle.
The top edge of the head for some clubs is so steeply inclined from the neck to the toe that the clamping action tends to cam the head out of its predetermined alignment within the fixture. Also the loft angle of the so called long irons #1 through #4 is so small that such clubs sometimes move out of alignment within the fixture during adjustment of the lie angle. It is accordingly another object to provide such a fixture having a toe stop readily adjustable where required to engage the toe of an iron in the fixture to prevent movement of the iron during adjustment of the lie angle, thereby to enable retention of the iron in the fixture with a minimum of clamping force.